CVE-2009-2839 in Mac OS X
Summary
by MITRE
Screen Sharing in Apple Mac OS X 10.5.8 allows remote VNC servers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via unspecified vectors.
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Analysis
by VulDB Data Team • 06/02/2025
The vulnerability identified as CVE-2009-2839 resides within Apple Mac OS X 10.5.8's screen sharing functionality, specifically affecting the VNC server implementation that enables remote desktop access. This issue represents a critical security flaw in the operating system's remote access capabilities, where malicious actors can potentially exploit the screen sharing service to gain unauthorized execution privileges or disrupt system operations. The vulnerability manifests through unspecified vectors that allow remote attackers to manipulate the VNC server component in ways that could lead to arbitrary code execution or denial of service conditions.
Technical exploitation of this vulnerability occurs through the VNC server implementation within the Mac OS X screen sharing service, where memory corruption issues can be triggered by malformed or malicious VNC client connections. The underlying flaw appears to stem from insufficient input validation and memory management within the VNC server code, allowing attackers to craft specific network packets or connection sequences that cause buffer overflows or other memory corruption conditions. These memory corruption issues can result in application crashes, system instability, or potentially more severe consequences including privilege escalation and arbitrary code execution within the context of the screen sharing service. The unspecified nature of the attack vectors suggests multiple potential entry points within the VNC implementation that could be exploited through various manipulation techniques.
The operational impact of CVE-2009-2839 extends beyond simple denial of service scenarios, as successful exploitation could provide attackers with unauthorized access to systems running vulnerable versions of Mac OS X. Remote attackers could leverage this vulnerability to execute malicious code on target systems, potentially leading to complete system compromise, data exfiltration, or use as a foothold for further network infiltration. The vulnerability particularly affects enterprise environments where screen sharing is commonly enabled for remote support or administrative purposes, creating potential attack surfaces that could be exploited by threat actors. Organizations relying on Mac OS X for business operations face significant risk if they have not patched this vulnerability, as it could enable attackers to gain persistent access to critical systems without requiring physical presence or local credentials.
Mitigation strategies for CVE-2009-2839 should prioritize immediate patching of affected systems with the latest security updates from Apple, as the vulnerability was addressed through official software releases. Organizations should disable screen sharing functionality on systems that do not require remote access capabilities, particularly in environments where the service is not essential for operations. Network segmentation and access controls should be implemented to restrict VNC server access to trusted networks and authenticated users only, reducing the attack surface for potential exploitation attempts. Security monitoring should be enhanced to detect unusual VNC connection patterns or suspicious network traffic that might indicate exploitation attempts. The vulnerability aligns with CWE-125 Out-of-bounds Read and CWE-129 Improper Validation of Array Index categories, while also mapping to ATT&CK techniques involving remote access tools and privilege escalation through service exploitation. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable screen sharing service, ensuring comprehensive protection against similar vulnerabilities in the future.